The invention relates to new ketolactones and to salts thereof, and to a process for their preparation.
The synthesis of heptanoic acids such as 6-oxo-7-(2-R.sup.2 -3-R.sup.3 -5.alpha.-hydroxycyclopentyl)-heptanoic acids useful in the preparation of prostanoic acid derivatives (wherein R.sup.2 and R.sup.3 are defined below) hitherto known exhibits considerable disadvantages. Thus it proceeds via a large number of stages, in which unstable intermediate products are formed. One of these stages is a reduction using diisobutylaluminum hydride, an expensive reagent and one which is difficult to handle on an industrial scale.